McLondon has added a paragraph about IgG4-related prostatitis to the page. I did some digging around and think it's better to remove the edit at this stage and perhaps add it back later in a modified form. My research showed that in one 2007 paper the prostatitis was described as Cat IV (" The present two cases complained of neither genitourinary nor pelvic symptoms and showed no granulocyte infiltration in the prostatic tissue samples. In this regard, they are classified as asymptomatic inflammatory prostatitis"). But in the study used as a source by McLondon, the symptoms are described so: "Patients almost exclusively presented with lower urinary tract symptoms such as dysuria, pollakisuria, urinary urgency, and a feeling of incomplete emptying". So these papers do not agree (although the second paper does use the first as a source!). These symptoms are not truly Cat IV, nor Cat I, II or III. This is an "other" form of prostatitis.

Possibly we should have a paragraph at the end of the page called "Other forms of prostatitis" that briefly describes these other forms of prostatitis? Ratel (talk) 09:21, 25 February 2015 (UTC)

@Ratel: I added the paragraph about IgG4-related prostatitis after reading a number of articles about it and IgG4-related disease (IgG4-RD). I do believe I summarised accurately the current knowledge surrounding IgG4-related prostatitis, backed by the couple of recent and valid references (from the past 14 months) that I provided.

IgG4-related prostatitis is not yet fully understood or widely known about so it remains under-recognised, but it is very much a confirmed cause of prostatitis, clearly fitting the Wiki definition of "histological (microscopic) inflammation of the tissue of the prostate gland". It can be associated with multi-organ involvement, just as in rheumatoid arthritis which is appropriately enough included on the arthritis wiki, and which is nowadays treated early and aggressively by rheumatologists... which eventually could conceivably occur with the steroid-responsive IgG4-RD.

I would think all validated causes of prostatitis (including sarcoidosis and other examples you mentioned above) merit inclusion somewhere on a Wiki page about prostatitis, irrespective of how and where they fit into a classification model designed for research more than 15 years ago. As you mentioned, causes (and I would include infections) should perhaps be included in a separate section on the Wiki. I personally wouldn't consider non-infective causes of prostatitis as 'other forms' though. They are just as much causes of prostatitis as infections are. Infections seem to be widely considered as the cause in only 5-10% of cases anyway.

Although exact symptoms of IgG4-related prostatitis might not be fully elucidated yet, in the paragraph I wrote I included those mentioned in a couple of recent studies as being particularly associated with it.

Regarding the 2007 paper you quoted above, this was obviously an early case study, just reporting on two 'histology' cases where positive IgG4 testing had been performed on prostate tissue samples. It was basically identifying more incidences of a newly recognised condition, not trying to characterise the condition. Despite what is mentioned in the paper's conclusion, neither case could reasonably be considered to be asymptomatic as both were diagnosed with benign prostatic hyperplasia, one requiring medication for the previous 24 years and the other one requiring surgery - the same surgery that provided the prostate tissue that got IgG4 tested 4 years later!

It was not really a study of prostatitis patients as such but did conclude, "From these points of view, we should carefully reevaluate patients with prostatitis and analyze clinical manifestations in a large number of patients with IgG4-related prostatitis."

Other studies into the condition include one from 2013 (Table 1 in the article includes a list of cases previously reported in other studies - mostly from Japan for reasons explained below) and one from Holland (database search which found 9 cases of prostatitis in 119 patients with established autoimmune pancreatitis).

As a background, IgG4-related disease was first recognised as a systemic condition in 2003 in Japan when extrapancreatic manifestations were identified in patients with autoimmune pancreatitis. As a result, a lot of the early research into IgG4-related disease was in Japan, and therefore the majority of cases reported seem to be among Asians with pancreatitis.

The first case of IgG4-related prostatitis was recognised around 2006 and has slowly become more recognised since. As most confirmed cases are identified from testing prostate tissue retrieved by prostate biopsy, TURP or prostatectomy, it follows that reported cases would be in men who tend to be the ones getting such procedures, i.e. older men. The naming as IgG4-related prostatitis was only recommended in 2012.

The NIDDK classification was described at the time (1999) by those involved in it as "research guidelines" "to address the confusion surrounding the diagnostic and treatment strategies in chronic prostatitis". It can still be used for classifying all prostatitis cases, whether cases are diagnosed as IgG4-related prostatitis or not, but it will fail to take pathology into consideration apart from infection and even then it doesn't address possible spread of infection to seminal vesicles or elsewhere in the reproductive tract which could be clinically relevant.

Classification is not necessarily making a diagnosis. Unlike Cat I, Cat IIIa is not in my view a clinical diagnosis, just a classification group. There's no reason why any Cat IIIa case would be immune to acquiring chronic bacterial prostatitis later on, then (if it's detected) get classified as Cat II instead, which would essentially hide the clinical reality that he would actually have a combination of at least two different conditions, one bacterial and one non-bacterial.

My understanding is that the NIDDK classification essentially subdivided symptomatic chronic prostatitis into 3 groups so that research could use "comparative evaluation" among somewhat similar groups of cases. At the time I doubt such research guidelines were intended to get used some 15 years later as a tool to ignore new discoveries about the condition(s) but were meant to aid make new discoveries.

Ultimately the Wiki page is not about the NIDDK classification though, even if it does currently dominate it. It's about a pathological condition (or conditions) with several causes, some known and others unknown. McLondon (talk) 10:41, 27 February 2015 (UTC)

I don't disagree with your points. The NIDDK classification system was never meant to cover all forms of prostatitis, just the commonest forms that are frequently confused. The other forms of prostatitis, which unlike the commonest forms are almost all subsidiary symptoms of systemic diseases, are relatively rare and covered under the articles on the diseases themselves (or if not, should be). My feeling is that this article needs to have a new section about other forms of prostatitis that occur as symptoms of other (wikilinked) diseases, such as IgG4-related pacreatitis. The section needs to mention the relative rarity as well, so as not to mislead or confuse readers. Have a go and let's see what you come up with. Ratel (talk) 13:44, 27 February 2015 (UTC)

@Ratel: Do you think we can add somewhere in the article about the controversy and discordance of type III etiology? There is this review article that mentions this in the section "2.3.1.Etiology and pathogenesis"